39... g6f5 [%c_effect f5;square;f5;type;Mistake;persistent;true] A serious inaccuracy, after which Black's position becomes surprisingly difficult. 40. d1h1 [%c_effect h1;square;h1;type;GreatFind;persistent;true] The rook is very annoying on the h-file. 40... e6f7 Preventing Rh5+. 41. h1h7  41... f5g6 